From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Schwidefsky Date: Mon, 18 Sep 2006 14:08:07 +0000 Subject: Re: [PATCH 2/6] Introduce CONFIG_ZONE_DMA Message-Id: <1158588487.31364.3.camel@localhost> List-Id: References: <20060911222729.4849.69497.sendpatchset@schroedinger.engr.sgi.com> <20060911222739.4849.79915.sendpatchset@schroedinger.engr.sgi.com> <20060918135559.GB15096@infradead.org> In-Reply-To: <20060918135559.GB15096@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig Cc: Christoph Lameter , linux-mm@vger.kernel.org, Nick Piggin , linux-ia64@vger.kernel.org, Marcelo Tosatti , Arjan van de Ven , Martin Bligh , KAMEZAWA Hiroyuki , Andi Kleen , linux-arch@vger.kernel.org On Mon, 2006-09-18 at 14:55 +0100, Christoph Hellwig wrote: > > Second, arches may use ZONE_DMA in an unknown way. We set CONFIG_ZONE_DMA > > for all arches that do not set CONFIG_GENERIC_ISA_DMA in order to insure > > backwards compatibility. The arches may later undefine ZONE_DMA > > if their arch code has been verified to not depend on ZONE_DMA. > > Let's pass this on to linux-arch so that the arch maintainers can give input > whether they need ZONE_DMA or not. If this just sneaks in unseen I'd bet > various architectures will just keept it around despite not needing it. s390 needs ZONE_DMA for the memory area below 2GB. That is required for the control structure of channel based I/O. It is not ISA but conceptually related. Can we rename GENERIC_ISA_DMA into GENERIC_IO_DMA or something similar? -- blue skies, Martin. Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH "Reality continues to ruin my life." - Calvin.